This invention relates to an ultrasonic transducer probe which may be used in inserting a cannula through a region of the body of a patient to be diagnosed, e.g., in a biopsy.
In the biopsy, tissues or body fluids may be extracted from the kidney, liver and other internal body organs by means of a suitable cannula for diagnostic purposes. Also, in X-ray angiography, a cannula with an injector is pierced into blood vessels and the like for injecting a contrast medium in examination for morbid changes in a brain, heart, abdominal organs, etc. Moreover, fluids may be extracted from a body. For example, amniotic fluids may be extracted from the uterus of a pregnant woman for diagnostic purposes, or blood or medication may be injected into a fetal body.
In all these cases, it is very important to prevent undue damage to essential organs or wrong extraction of tissues in the use of the probe.
Such apparatus is described, for example, in U.S. Pat. No. 4,108,165 issued Aug. 22, 1978, to Edward L. Kopp et al. under the title "Transducer Probe for Pulse-Echo Ultrasonic Exploration." In this patent is taught ultrasonic diagnostic transducer apparatus and a combination of such apparatus and a cannula guide means, whereby an ultrasonic beam is transmitted into the body of a patient to be examined, and a sectional image of the interior of the body is obtained by reproducing the ultrasonic-echo pulses of the beam on a picture screen. The cannula is inserted into the body while the positional relation between the cannula and the internal region to be examined, as well as the state of the cannula, is reflected on the picture screen.
Apparatus is also known in which a carrier, having ultrasonic transducer elements arranged thereon, includes a tapered cannula guide slot, whereby the movement of the cannula may be observed by watching a sectional image plane in the body of a patient while the ultrasonic transducer elements are driven successively, the direction of the cannula being optionally selected within a fixed range. This apparatus is described in U.S. Pat. No. 4,029,084, issued on June 14, 1977, to Richard Soldner, and entitled "Ultrasonic Applicator with Guide Slot for Puncturing Cannula."
U.S. Pat. No. 4,289,139, issued on Sept. 15, 1981 to Susumu Enjoji et al., and assigned to the assignee of this invention, describes an ultrasonic transducer probe having a removable cannula guide block with a triangularly shaped lateral cross section. The block is fitted into a cavity of complementary shape in the probe and includes a cannula guide slot with a wide opening lying along the wide portion of the block and tapering toward the application surface. A narrow slot in the guide block interconnects the guide slot in the face of the block for permitting the block to be removed while the cannula is maintained in its proper position. This arrangement facilitates the taking of X-ray photographs in some cases. The removable block also simplifies the sterilization of the apparatus.
An improvement in the apparatus of U.S. Pat. No. 4,289,139 is taught in U.S. Pat. No. 238,203, filed Feb. 26, 1981, by Susumu Enjoji under the title "A Probe for Ultrasonic Imaging Apparatus," now U.S. Pat. No. 4,408,611. In this improvement, the structure of the removable guide block permits easier and more precise insertion of the block into the probe and facilitates the removal of the block from the probe.
In the above-described examples, however, relative displacement between the carrier body and the cannula is required to remove the carrier of the probe from the surface of the patient while maintaining the state and position of the inserted cannula. For this reason an operational difficulty can be present. In many cases where X-rays need to be taken, it would be very advantageous to be able to remove the entire transducer probe while maintaining the cannula in proper position.
In accordance with the foregoing, it is a general object of the present invention to improve ultrasonic transducer probes for use in inserting a cannula through a region of the body of a patient to be diagnosed, which facilitates the operation and the taking of X-rays of the area under diagnosis.